The understanding of the dynamics of distribution and variation of precipitations is of utmost importance for the Climatologia and for Meteorology, as well as, they are basic in other branches of the scientific knowledge, mainly on ones to the study of the economic activities, after all, the distribution of rains and mainly the variability of these is determinative in practical farming and the agricultural ones. The study of the behavior and the dynamics of variation of precipitations they are mechanisms more necessary technician each time for the success of the production of the farming sector, for this, is marcante the increase of methodologies used for intermediary of agricultural meteorology. * Permitted in Geography, and substitute professor in the course of Licenciatura/Bacharelado Geography of the Federal University of the Acre? .